Analysis of the Implications of Main Field Entities On Commutation in Field Regulated D.C. Motors

The paper applies a detailed field analysis by means of the finite element method to the study of the commutation in a d.c. motor speed-regulated by main field weakening; by comparing the resulting flux density diagrams in interpole airgaps to an ideal reference diagram, more reliable predictions about commutation are drawn than from usual evaluations. The method allows also some improved criteria for design purposes to be outlined.